<!DOCTYPE html>
<html>
<head><title>rAF test</title></head>
<body>
<canvas id=c width=300 height=300></canvas>
<script>
c = document.getElementById('c');
x = c.getContext("2d");
x.fillStyle = 'black';
x.fillRect(0, 0, c.width, c.height);
function raf() {
    x.fillStyle = 'red';
    x.fillRect(
        Math.random() * c.width,
        Math.random() * c.height,
        Math.random() * 10,
        Math.random() * 10
    );
    requestAnimationFrame(raf);
}
requestAnimationFrame(raf);
</script>
</body>
</html>
